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Plasticity of spine morphology is a universal phenomenon in rotifers. Some Brachionus calyciflorus clones consistently develop two posterolateral spines (PS) with similar length (Type A), but others (Type B) not. The underlying mechanisms remain unknown. In the present study, the resting eggs were collected from the same B. calyciflorus strain, their hatchlings (stem rotifers) were categorized into types A and B, and then, clonally cultured for eight generations at different algal densities or temperatures. The results showed that the PS varied in length among different temperatures and food levels, but inherent differences between types A and B were always observed, indicating that differentiation between types A and B might not associate with temperature or food availability. Next, we compared the population growth and PS length between types A and B at the general condition (control), in responses to Asplanchna kairomone, Keratella tropica and Moina macrocopa. The results showed that type B had higher population growth rate than type A, suggesting the higher adaptability of type B in the general condition. In response to Asplanchna kairomone, the PS length of both types A and B was significantly induced, and their PS length was similar, but type B showed higher population growth rate than type A. Coculture with M. macrocopa significantly lengthened the PS of type B but not type A, and types A and B showed similar population growth curves. Coculture with K. tropica did not affect significantly the PS length of types A and B. However, type A showed significantly and greatly higher population density and population growth rate than type B, indicating a much stronger competition ability of type A than type B against K. tropica. Overall, these results indicated that consistent development of PS might facilitate B. calyciflorus to defend against small competitors.

Abstract Urban heat and air pollution, two environmental threats to urban residents, are studied via a community science project in Los Angeles, CA, USA. The data collected, for the first time, by community members, reveal the significance of both the large spatiotemporal variations of and the covariations between 2 m air temperature (2mT) and ozone (O3) concentration within the (4 km) neighborhood scale. This neighborhood variation was not exhibited in either daily satellite observations or operational model predictions, which makes the assessment of community health risks a challenge. Overall, the 2mT is much better predicted than O3 by the weather and research forecast model with atmospheric chemistry (WRF‐Chem). For O3, diurnal variation is better predicted by WRF‐Chem than spatial variation (i.e., underestimated by 50%). However, both WRF‐chem and the surface observation show the overall consistency in describing statistically significant covariations between O3 and 2mT. In contrast, satellite‐based land surface temperature at 1 km resolution is insufficient to capture air temperature variations at the neighborhood scale. Community engagement is augmented with interactive maps and apps that show the predictions in near real time and reveals the potential of green canopy to reduce air temperature and ozone; but different tree types and sizes may lead to different impacts on air temperature, which is not resolved by the WRF‐Chem. These findings highlight the need for community science engagement to reveal otherwise impossible insights for models, observations, and real‐time dissemination to understand, predict, and ultimately mitigate, urban neighborhood vulnerability to heat and air pollution.

This paper reports the design, synthesis, and antibacterial activity study of pleuromutilin derivatives with 2‐methyl‐4‐nitroaniline and 2‐methoxy‐4‐nitroaniline side chains at the C22 position. The structures of the new compounds were characterized by 1H‐NMR, 13C‐NMR and HRMS. The inhibitory activity of the compounds against MSSA, pyogeniccoccus, streptococcus, and MRSA strains was determined using the micro broth dilution method. The results showed that the compounds exhibited certain activity against Gram‐positive bacteria, among which compounds A8a, A8b, A8c, A8d, and A7 demonstrated superior antibacterial activity against MSSA, MRSA, and pyogeniccoccus compared to tiamulin, although the derivatives showed lower antibacterial activity against streptococcus compared to the control drug. Based on the favorable in vitro activity of A8c, the time‐kill kinetics against MRSA were evaluated, revealing that compound A8c could inhibit bacterial proliferation in a concentration‐dependent manner. [ABSTRACT FROM AUTHOR]

To better assess the practical value and avoid potential risks of the traditionally medicinal and edible basidiomycete Schizophyllum commune, which may arise from undescribed metabolites, a combination of elicitors was introduced for the first time to discover products from cryptic and low-expressed gene clusters under laboratory cultivation. Treating S. commune NJFU21 with the combination of five elicitors led to the upregulated production of a class of unusual linear diterpene-derived variants, including eleven new ones (1–11), along with three known ones (12–14). The structures and stereochemistry were determined by 1D and 2D NMR, HRESIMS, ECD, OR and VCD calculations. Notably, the elongation terminus of all the diterpenes was decorated by an unusual butenedioic acid moiety. Compound 1 was a rare monocyclic diterpene, while 2–6 possessed a tetrahydrofuran moiety. The truncated metabolites 4, 5 and 13 belong to the trinorditerpenes. All the diterpenes displayed approximately 70% scavenging of hydroxyl radicals at 50 μM and null cytotoxic activity at 10 μM. In addition, compound 1 exhibited potent antifungal activity against the plant pathogenic fungi Colletotrichum camelliae, with MIC values of 8 μg/mL. Our findings indicated that this class of diterpenes could provide valuable protectants for cosmetic ingredients and the lead compounds for agricultural fungicide development. [ABSTRACT FROM AUTHOR]

The fermentation of a soil-derived fungus Acremonium sp. led to the isolation of thirteen ascochlorin congeners through integrated genomic and Global Natural Product Social (GNPS) molecular networking. Among the isolated compounds, we identified two unusual bicyclic types, acremochlorins O (1) and P (2), as well as two linear types, acremochlorin Q (3) and R (4). Compounds 1 and 2 contain an unusual benzopyran moiety and are diastereoisomers of each other, the first reported for the ascochlorins. Additionally, we elucidated the structure of 5, a 4-chloro-5-methylbenzene-1,3-diol with a linear farnesyl side chain, and confirmed the presence of eight known ascochlorin analogs (6–13). The structures were determined by the detailed interpretation of 1D and 2D NMR spectroscopy, MS, and ECD calculations. Compounds 3 and 9 showed potent antibacterial activity against Staphylococcus aureus and Bacillus cereus, with MIC values ranging from 2 to 16 μg/mL. [ABSTRACT FROM AUTHOR]

The foundation of an offshore wind turbine (OWT) accounts for up to 20% of the total cost; therefore, investigations into reliable and efficient foundations are important for the offshore wind energy industry. This article describes an innovative winged caisson foundation for OWTs, which adapts the conventional caisson foundation to produce higher overturning capacities. The behaviour of this proposed novel foundation in the sand was investigated through experimental and numerical modelling using a series of 1 g tests (1/70th scale), centrifuge model tests (70 g ), and finite element (FE) simulations. Models with various wing sizes installed in different sand densities were tested in the laboratory by applying an overturning load. In this article, the moment–rotation performance of the foundation under monotonic loading is compared against that of conventional caissons to assess the potential benefits of adding wings to caisson foundations. Results show that there is a significant increase in overturning capacity provided by the novel foundation. FE models were first validated against experimental results, then, used to conduct a parametric study to better understand the behaviour of the winged caissons beyond the scaled model tests. In addition, the FE models were used to evaluate the drained response of the proposed foundation under combined loading. [ABSTRACT FROM AUTHOR]

Planktonic archaea and bacteria play important roles in biogeochemical cycling, but their biogeographical patterns and underlying ecological processes remain poorly understood, particularly in large‐scale rivers.We collected 43 water samples covering a 2279 km reach of the Jinsha River, one of the largest rivers in southwest China, and performed high‐throughput sequencing analysis on planktonic archaeal and bacterial communities. Partial Mantel analysis and neutral model were used to assess the factors influencing microbial distributions. The associations among different microbial species and their geographical distribution patterns were linked through co‐occurrence networks, and the putative key taxa in the archaeal and bacterial networks were analysed.The Shannon index of both archaeal and bacterial communities was highest in the midstream reach. The Pielou's evenness of archaea did not vary among the three reaches, whereas those of bacteria increased from upstream to downstream. The archaeal and bacterial community compositions were significantly different in the three reaches, but the differences among the bacterial communities were greater than among the archaeal communities.Both dispersal limitation and environmental selection affected the community compositions of the archaea and bacteria, but dispersal limitation was the most influential factor. Compared to archaea, bacteria were less affected by dispersal limitation and more by environmental selection.The co‐occurrence network analysis demonstrated that, compared with the bacterial network of all sites, the archaeal network with larger graph density had higher connectivity and complexity, but a lower proportion of negative correlations. The putative key taxa belonged to Nitrososphaeraceae and Candidatus_Nitrocosmicus from the archaeal community, and Hydrogenophaga and Sphingorhabdus from the bacterial community.Taken together, these findings demonstrated that the planktonic archaea were more dispersal‐limited and showed more network connectivity than the planktonic bacteria in the Jinsha River. This study enhances our understanding of the biogeographical distribution patterns and underlying ecological processes of planktonic microorganisms over large‐scale freshwater systems. [ABSTRACT FROM AUTHOR]

The concrete structure in the coastal area suffers from the combined erosion of sulfate and dry–wet cycles. In this study, in order to modify ordinary concrete, fly ash, slag powder, silica fume and polyester fiber are added separately. The crack resistance of concrete was studied through mechanical performance test and three-point bending fracture test of notched beam under sulfate dry–wet cycles. The load-crack opening displacement (P-CMOD) curve characteristics, fracture toughness and fracture energy of modified concrete after corrosion are calculated and analyzed. Results reveal that the P-CMOD curve of modified concrete after corrosion has gone through four stages of damage: initial bending section, proportional elastic section, stable expansion section and softening section. With the increase of dry–wet cycles, the overall corrosion resistance and toughening coefficient of modified concrete increases first and then decreases. Adding 25% fly ash can significantly enhance the fracture toughness of concrete in the initial stage. The addition of polyester fiber and slag is beneficial to the improvement of the instability toughness and fracture energy of the concrete in the later stage.

EPA reports a steady decline of US anthropogenic NO _x emissions in 2005–2019 summers, while NO _2 vertical column densities (VCDs) from the OMI satellite over large spatial domains have flattened since 2009. To better understand the contributing factors to a flattening of the OMI NO _2 trends, we investigate the role of soil and lightning NO _x emissions on this apparent disagreement. We improve soil NO _x emissions estimates using a new observation-based temperature response, which increases the linear correlation coefficient between GEOS-Chem simulated and OMI NO _2 VCDs by 0.05–0.2 over the Central US. Multivariate trend analysis reveals that soil and lightning NO _x combined emissions trends change from −3.95% a ^−1 during 2005–2009 to 0.60% a ^−1 from 2009 to 2019, thereby rendering the abrupt slowdown of total NO _x emissions reduction. Non-linear inter-annual variations explain 6.6% of the variance of total NO _x emissions. As background emissions become relatively larger with uncertain inter-annual variations, the NO _2 VCDs alone at the national scale, especially in the regions with vast rural areas, will be insufficient to discern the trend of anthropogenic emissions.